1. Field of the Invention
The present invention relates to a technology for identifying an operator who has operated an in-vehicle system.
2. Description of the Related Art
A car navigation system including a television service is generally equipped to a vehicle. Such a car navigation system has been developed from a conventional type, which has a single display screen that displays thereon either a car navigation data or a television program, to a new type, which has a dual-view liquid crystal display (LCD) that displays thereon different images for each of a driver seat and a passenger seat by using a touch panel or a remote controller.
Although the new type of the car navigation system can display different images and operation screens for each of a driver in a driver seat and a passenger in a passenger seat, an input unit (e.g., a touch panel) is shared by the driver and the passenger. Therefore, it is difficult for such a car navigation system to distinguish operators from one another for each of different images displayed on the dual-view LCD. For example, even when a passenger operates a touch panel to turn the volume up on a television, a car navigation system may erroneously determines that it has received an operation for changing a display type of the car navigation system from a driver in a driver seat. As a result, an operation different from that intended by the passenger may be erroneously performed.
For counteracting above problems, a conventional technology for distinguishing an operation by a driver from an operation by a passenger has been disclosed in Japanese Patent Application Laid-Open No. 2006-47534.
In the conventional technology, electric current having different frequencies are respectively supplied from respective power sources to a driver seat and a passenger seat, so that it is possible to distinguish an operation by a driver from an operation by a passenger by detecting supplied electric current from a touch panel and determining its frequency.
However, the conventional technology has a problem that frequency of electric current may be erroneously detected due to noise. Therefore, it is difficult to accurately identify an operator.